Wireless local area networks (WLANs) are increasingly available for accessing the Internet and for telephony applications such as Voice over Internet Protocol (VoIP) applications. The IEEE standard 802.11 is a widely adhered-to standard specifying architecture and protocols for WLAN operation. In a typical WLAN deployment using the IEEE 802.11 standard, a set of access points (AP) are connected to a common backbone called a distribution system. The distribution system serves to transfer data between the access points, or from an access point to an external network such as the internet via a gateway. Each access point is the master device in a Basic Service Set (BSS) subnet of wireless stations (STA), and serves to relay data between these stations, and between each of these stations and the distribution system.
When the capacity of a single AP does not meet the required network traffic load in a planned coverage area (i.e., hotspot), multiple APs operating on different channels may be installed with overlapping coverage. The use of multiple APs with overlapping coverage also improves the reliability of the network, due to the inherent redundancy of such a scheme in the case of a single failed AP.
If the intended coverage area is outdoors, there arises the problem of how to provide the APs with power, which is traditionally supplied over a wired connection in an indoor environment. As more widespread deployment of WLANs in an outdoor environment occurs, the problem of managing power to the APs becomes more critical. Solar-panel powered wireless APs called solar nodes (SN) are commercially available. These allow the outdoor deployment of WLANs, even in areas where no traditional source of power for the network is available. The size of solar panel and battery required to provide adequate power is a key driver of cost for the SN. Managing power in such a WLAN is crucial in order to conserve battery power in the SNs, and also to minimize the size of solar panel required to power each of the SNs.
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